Dear friends,
We have recently been experiencing noise in the lock channel of our
1985-vintage AM-250. This noise can be observed at the output of the lock
receiver board, independent of whether or not the spectrometer is locked,
so it is not simply a display artifact. The filtered output contains
filtered noise. Computer operations such as PX, TR, and GS (but not GO)
reduce this noise to a normal level while they are occurring. However,
turning off the computer or unplugging the lock input to the GDP have no
effect. The reference frequencies all look clean and unchanged whether or
not the noise is present. The lock transmitter output does not appear to
change although the signal level is low enough that it's hard to tell.
Has anyone out there seen this effect or have some clever ideas on pinning
it down?
Thank You,
Kenner
Kenner Christensen
Chemistry Department NMR Facility
University of Arizona
Tucson, Arizona 85721
(520) 621-2308
Somos pocos, pero estamos locos
Received on Mon Jul 31 2000 - 16:31:53 MST